Flash-light meter.



M. X. CORCGRAN.

FLASH UGHT METER.

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mr neufs uns ca. mmunm. mxumnmu u c M. x. coRconAN.' n AsH uam Mms. l APPLICATION FILED OCT. 22. i915.

2 SHEETS-SHEET 2.

' m Eri-LER /V X60/60mn.

UNITED STATES PATENT OFF-.ICE

MTTZX. COR-CORAN', 0F VALPARAISO, INDIANA.

FLASH-LIGHT METER.

Application led October 22, 1915. Serial No. 57,235.

To all 'whomJ t may concer/n.'

Be it known that I, Mo'r'r X. CoRooRAN, a citizen of the United States, and a resident of the city of Valparaiso, in the countyof Porter and State of Indiana, have invented certain new and useful Improvements in Flash-Light Meters; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, and to the numerals of reference marked thereon, which form a part of this specification.

In photography, the required time of eX- posure is governed by a number of conditions such as the lighting of the object to be 'photographed the size of the diaphragm opening, the rapidity of the plate or lm and the character of the lens, all of which make it very difficult for an inexperienced photographer to take good pictures.

In flashlight photography, the timing of the exposure is accomplished by varying the quantity of iashlight substance employed and in determining the quantity of flashlightsubstance t0 be used, it is necessary to take into consideration the efliciency of the flashlight substance, the size ofthe diaphragm used, the rapidity of the plate or film, the speed of the lens, etc., and the quantity of flashlight substance used must be varied accordingly in order to givethe proper degree of illumination for taking the picture. It is usually rather dicult particularly for an amateur to determine or measure the required quantity of ashlight substance on account of the variations in the quantity required because of the above conditions, and also because the quantity or' flashlight substance required does not vary in direct proportion to theA distance of the object from the camera.

It is an object of my invention to provide meansjwhich can be readily understood and used by an ordinary amateur photographer for determining the quantity of iiashlight substance required under various conditlons.

Another object of my invention is to provide a means for measuring fiashlight substances which is marked toindicate the quantity of fiashlight material to `be used under normal conditions for various dis tances.

Another object of my invention is' to provide means for measuring flashlight substances whichy shows `the quantity of flash- Specifcation of Letters Patent.

Patented Dec. 1o, 1918.

light substance to be used for each diaphragm opening under normal conditions for the various distances.

Another object of the invention is ,to provide ameans for measuring fiashlight substances having a scale for determining the quantity of flashlight substance to. be used under normal conditions at various distances and to provide in coperative relation withthe said scale, another scale for correcting the measurement of the quantity of flashlight material to be used to accord with conditions which vary the` eifective ness of the flash. i

Another object of the invention isv to prouring device, having a scale for measuring the quantity of flashlight -materia1v to be used, a magazine which does not enlarge the measuring device and which comprises a supplemental holder from which a supply of flashlight substance containedV therein can be poured into the measuring device.

Other and further important'objects of my invention will be apparent from the dise closure in the specification and drawings. f The invention (in a preferredform) is illustrated in the drawings and hereinafter more fully described.

In the drawings: Y Figure 1 is a side elevation. of a device embodying the principles of my invention shown closed and`v in zero position. e Fig. 2 is a similar view thereof .partly broken away, illustrating the same in 'an adjusted position with parts removed.

vvide in connection with a flashlight meas- Fig. 3 is a view ofa detached member of .i

a modified form of device. .v Y Fig. 4 is a view somewhat similar toFig, 2, showing a quantity of powderv being measured. s Fig-5 is a sectional view device illustrated in Fig. l.

Fig. 6 is a developmentview of the scale member shown in Figs. 1, 2, and 4. v

Fig. 7 is an end viewof the device shown invFig. 2. F Fig. 8 is a section taken on line 8 -8 of Fig. 9 is a similar section of a modified form of device. a Fig. 10 is asimilar modified form of device.` A

VFig. l1 is a similar sectionv of ,still Aan:` other modiied'form of device.

Fig. 12 is. a development view 'illustrating' of the formi f E structed'of any suitable another arrangement of indicating and computing scales. Y

Fig. 13 is a view similar to Fig. 1:2, of another type of indication scale.

Fig. 14 is an elevation of a measuring container with a uniformly graduated distance scale thereon.

As shown in the drawings:

l The device consists of a tubular shell or casing,VV open at bothy ends, indicated by the reference numeral 1i, and in the present instance shown rectangular in cross section, (thoughof course the`- section may be of any shape` desired) and'said shell may be conmaterial, such as paper, liber, or metal. Slidable in said rectangular shell 1, and frictionally held from accidental movement therein, is a rectangular graduated element 2, which may be solid or hollow, as desired, but-in either event closed at oneV end, and ofa length, as clearly shown in Fig. 1, slightly greater than the tubular shell, so as to project beyond the same at the lower end thereof.

. 'As'clearly shown in Figs. 1, 2, il, 5, and 7,

the movable element 2,' has four side walls, each one of whichisgraduat-ed, the graduations on each of three of the scales representingV distances inv feet from flash to subject for a certain diaphragm openingV noted below the scaleboth inthe f and U.S. systems. Inasmuchv as therillumination of the subject varies reversely as the square ofthe distance of the flash from thev subject,fa simplelproportion does not exist between .theVY quantities of substance. required and distance of the source of lightfrom the subject, so that in order to properly measure the, substance it is necessary that 'the scales representingthe distances be laid out accordingto `certain `curve equations. This is in `order thatnthey proper increments of movementoffthe'element 2, within the shell 1:, maybe Obtainedto afford a co-mpartment of the properdimensions atthe upper end of the'device" intowhich the substance, de notedby the letter X, is poured for measurement Y is shown in the development view in Fig, 6, the first scale represented is for a diaphragm opening of f1.6 or U.S.16, which is a comparatively small aperture; T he'next scale is gradu atedjfor a diaphragm stop` of 113 or U.S.8, and this stop opening istwice theV area' of the f.16`or 15.316 stop, and of course admits twice as much light, Consequently the distance scalel for the f.11.8 or 115.8 stop differs from ythe rst scaleV in that the'V graduations representing the'rdistances in feet arey only on'e'half as far apart, and the Volume of the compartment formed atthe top ofthe device to receivethe powder measured, is onlvone half as greatVV for a given distance as that for Vthe first scale. Similarly Von the third described scale', varies accordingly,

beingy either one half or one fourth as large, as the case may be. That is to say, for a given distance, say twenty feet of the source of light from the subject, by using the first scalea certain volume of powder is necessary, and using the second scale, that vis with a larger diaphragm opening, only half as much powder is necessary, and using the third scale, that iswith a diaphragm opening four times as large, only one fourth the quantity of flash substance is required.

The fourth scale shown has even graduations numbered similarly to the other scales, from the bottom of the insert 2, and is useful for calculating corrections, toV be made on account of certain vconditions, to the quantity of flashlight'V material as determined by the other scales. For instance, setting the element 2, for eighteen feet on the USS scale, a corresponding reading of 18 would be obtained upon the factorial scale. If the particular kind or quality of the flash substance to be used has only one half they illuminating power or intensity for which the distance scale for USB stop is calculated` it will be necessary to use twice the amount of flashlight substance. The other scales have unevenV graduations and cannot readily be used for proportionate adjustments and for this reason the factorial scale is provided. ln the illustration stated the factorialr scale setting 18 is multiplied by two, giving 36 and the factorial scale is then set to 36 and this will give the proper volume at the upper .end ofthe device for the required quantity of flash substance to be used. On the other hand for the same setting, that is eighteen feet on the USS scale.l supposing a plate or film is to be used which is twiceV as fast as that for which the distance scale is calculated, then the factorial scale reading 18 must be divided by two. and the movable element 2 is adjusted for such a reading on the factorial scale, so that the compartment formed at the upper endv of the device isof the proper size to measure. the necessary quantity of flash required for the picture;

It is obvious that a number of corrective factors may be rmultiplied into one another to obtain new readings on the factorial scale, and the'movable elementQ, is then finally set according to the new reading obtained, irrespective of the readings on the distance scales, the same merely being used for an initial setting to obtain an initial reading on the factorial scale for a given set of conditions. Itis clearly obvious that the factorial scale may have a number of applications for the computation of corrections depending on many different conditions.

In the sectional view of the device illustrated in Fig. 5, I have shown, as before, a rectangular tubular shell or casing 3, the movable element being denoted by the reference numeral 4, and consisting of a rectangular tube closed at its upper end and open at its lower end and slightly greater in length than the shell 3, and provided with a scale as before. Inserted within said element 4, at the lower end thereof, is another tubular member 5, which Hts tightly therein, and may contain a quantity of Hash powder Y. Thus in using the device the movable element 4, is set to the proper indicating mark on one ofits scales, and the tubular container 5, is withdrawn and a certain quantity of the powder therein emptied into the compartment formed at the upper end of the device, to fill the same and thus obtaining the quantity of powder required.

Of course if so desired the device may be made hexagonal, as shown in Fig. 9, or cylindrical, as shown in Fig. 10, wherein the outer shell is denoted by the reference numeral 6. the adjustable tubular scale carrying member by the reference numeral 7, and the flashlightv powder container by the reference numeral 8. In Fig. 11, I have illustrated a modified form of device for measuring Hashlight strips which may be furnished in different lengths of a certain width, and the proper quantity or length required may be readily obtained by projecting or inserting the end of the sheet into the enevelop or container 9, when the indicating card or movable element 10, therein has been moved to an adjusted position for a certain setting on the distance scale provided. Instead of actually inserting the Hashlight strip therein for measurement, the scale on the movable member may denote in inches or other unit lengths, the proper amount or length of Hashlight sheet necessary, and a measuring scale may be laid oH' on the movable member 10, by which the sheet may be measured oif.

In the modified form of device illustrated in Fig. 12, I have shown a development view of a movable member 11, provided with curves for certain distances, one curve being provided for each distance selected. The points at which these distance curves cut the parallel vertical lines representing the diaphragm openings are points for setting the movable member in the container for obtaining a proper volume of Hash powder. The

development view also shows 'a factorial scale with convergent lines drawn thereacross for graphically computinga new result where a factor greater or less than l, is introduced for consideration.- The main factorial scale is graduated along the vertical 1 line similarly to that described with reference to Fig. 6, and on each side of the 1 line are parallel lines representing factors greater than 1, to-wit 2, l, 1%, l, and and i. The convergent-lines cut the vertical lines proportionate distances apart, so that if the factorial scale reads 10 and the factor to be multiplied thereinto is 112, the convergent line cutting the 1 line at 10 is traced along until the point at which it cuts the J2- line is found and this point which will correspond to 5 on the 1 line is the proper setting for the movable member.

In Fig. 13 in place of using-curves to ascertain the various points on the scales, I haveV laid 0H the divisions on a movable element 12, both on the distance and factorial scales, and printed the actual computed numerical values at the diHerent points. Fig. 14 represents a transparent container 13, of varying cross sectional area, for measurement of Hash powder ,with a distance scale graduated thereon, the graduations of which, due to the shape of the container, are spaced equidistantly apart.

It is obvious that other scales may be provided upon the movable member, for instance solar scales for use in daylight work for the determination of different factors to be considered with certain ones given. A similar device may be readily constructed for the measurement of magnesium ribbon, that is to say a scale may be calculated and described upon the movable element 2, of the form of device first described to give the required length of ribbon necessary for a given distance from the source of light to subject and a given diaphragm opening. It is obvious also that my invention is capable of a converse use, that is, for the determination of proper distances between Hash and subject for a given or predetermined quantity of powder. Then, too, my invention may be readily combined with instruments or mechanisms for actually measuring the distance between the subject and Hash .without departing from the principles of my invention.

I am aware that various other details of construction may be varied through a wide range without departing from the principles of my invention, and I therefore do not purpose limiting the patent granted otherwisel than necessitated by the prior art.

I claim as my invention:

1. A container for measuring Hashlight material for photographing purposes, comprising a member having a distance indicating scale and having means coperating with the said scale member for varying the capacity of the container, the said scale member being graduated so that when the said means is adjusted to indicate on the scale the distance between the flash and the object to be photographed, the container will measure the amount of flashlight material required for taking the picture at the distance indicated by the scale.

2. A container for measuring flashlight material, comprising a member having a plurality of differentdistance indicating scales, each suitably marked to correspond with the designation of a diaphragm opening of a photographing machine, said container having means cooperating With the said scale member, for varying the capacity of the container, the said scale member being graduated so that when said means is adjusted to indicate on the scale the distance between the flash and the object to be pho- `tographed, the container will measure the amount of flashlight material required for taking the photograph at the given distance.

Copies of this patent may be obtained for 3. A container for measuring flashlight material for photographing purposes, comprising a nieinber having a main scale and an auxiliary' scale and having means cooperating With the said scale member for varying the capacity of the container, the said main scale consisting of uneven distance indicating graduations cooperating with the said means so that when the said means is adjusted to indicate on said scalel the distance between the flash and the object to .be photographed, the container will hold the quantity of flashlight material required at the said distance and the said auxiliary s tale consisting of even graduations for proportional adjustment of the volume of the container. Y

In testimony whereof l have hereunto subscribed my name in the presence of' tvvo subscribing Witnesses.

HOTT X. CORCORA.

Witnesses CHARLES W. HILLS, Jr.. EARL M. HARDiNn.

ve cents each, by addressing the Commissioner of Patenti,

Washington, D. C. 

